The present invention relates to a metal material and a method of producing the same, and a carbon fiber-metal composite material and a method of producing the same.
In recent years, a composite material using carbon nanofibers has attracted attention. Such a composite material is expected to exhibit improved mechanical strength and the like due to inclusion of the carbon nanofibers.
As a casting method for a metal composite material, Japanese Patent Laid-Open No. 10-183269 proposes a casting method which causes magnesium vapor to permeate and become dispersed in a porous formed product formed of oxide ceramics while introducing nitrogen gas to cause a molten metal to permeate the porous formed product.
However, since the carbon nanofibers have strong aggregating properties, it is very difficult to uniformly disperse the carbon nanofibers in a matrix of a composite material. Therefore, it is difficult to obtain a carbon nanofiber composite material having desired properties. Moreover, expensive carbon nanofibers cannot be efficiently utilized.
Since the related-art casting method which causes a molten metal to permeate a porous formed product formed of oxide ceramics involves complicated processing, it is difficult to achieve production on an industrial scale.